If he's not, well, then it's a different story.
"It's just been an inconsistent pitch from pitch to pitch," Hernandez said. "I've got to find a way to be more consistent with it."
Saturday against the Braves, Hernandez could not control the curve. He hit the first two batters he faced with it and it didn't take long for the Atlanta hitters to realize they could sit on his fastball and he allowed four runs in one-third of an inning.
So even if the pitches he made to Jason Heyward and Justin Upton in the outing were not bad ones, they were expected fastballs that led to hits and runs.
"Even the pitches to Heyward and Upton were pretty good pitches," Hernandez said. "But when you can't throw a curveball over and all you have to look for is a fastball, that makes it pretty easy to narrow it down."
D-backs manager Kirk Gibson said the issue might also be with Hernandez's mechanics.
"We came in and looked at the film and it looked like he was throwing across his body, looked like he was too closed," Gibson said. "I don't think his breaking ball has had as much depth or movement as its had this whole year."
Gibson also noted that Hernandez has been much better at home (2.12 ERA) than on the road (6.87).
When asked if there was anything to that, Gibson said, "If it continues, there is."
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.